KR20230037863A - Base station and control method thereof - Google Patents

Abstract

The present invention provides a new adaptive channel estimation technique capable of minimizing downlink transmission performance degradation even for user equipment (UE) moving at high speed by reflecting mobility of the UE to enable accurate channel estimation based on a CSI report according to bundled CSI-RS transmission & CSI report for the UE moving at high speed.

Description

Base station apparatus and method of operating base station apparatus {BASE STATION AND CONTROL METHOD THEREOF}

The present invention relates to a downlink channel estimation technique using a downlink reference signal (RS).

In the LTE system, a cell-specific RS (CRS) allocated to the entire cell is used as a reference signal (RS) used to know a channel state between a base station and a terminal.

However, the use of such a CRS has limitations limiting the flexibility of network configuration and inefficiency in terms of energy. In addition, the use of CRS is difficult to apply to a high-frequency region of 6 GHz or higher and is not suitable for a multi-input multi-output (MIMO) system using a plurality of antennas.

Therefore, in NR (5G) using the MIMO system and high-frequency domain, instead of using the CRS that has been used in LTE, various types of RSs suitable for various situations of the terminal (UE) are defined, and RSs suitable for each beam of MIMO By giving and receiving, it is evolving to be able to respond to different frequency bands and various scenarios.

As such, among RSs defined in 5G, Channel State Information (CSI)-RS is an RS defined to estimate the state of a downlink channel transmitted from a base station (gNB) to a terminal (UE).

In the downlink channel estimation process using the CSI-RS, when the base station (gNB) transmits the CSI-RS, the terminal (UE) checks/identifies the state (state) of the downlink channel based on the received CSI-RS. and reports the result (CSI) to the base station (gNB), and the base station (gNB) estimates the state (situation) of the downlink channel with the terminal (UE) based on the received CSI Report. Accordingly, the base station (gNB) can perform downlink scheduling (eg, modulation scheme, code rate, number of transmission layers, MIMO precoding, etc.) based on channel estimation through the CSI Report for the terminal (UE).

On the other hand, when the terminal (UE) moves at high speed, the downlink channel environment is unstable due to the high-speed movement environment of the terminal (UE), so transmission performance is deteriorated according to downlink scheduling based on channel estimation through the CSI Report. may occur.

However, in the current standard, a method for realizing accurate channel estimation based on a CSI report is not proposed even in a high-speed movement environment of a terminal (UE).

Therefore, in the present invention, to propose a new type of adaptive channel estimation technology that enables accurate CSI-based channel estimation even while the UE is moving at high speed by reflecting the mobility of the UE. do.

The present invention was created in view of the above circumstances, and the problem to be solved in the present invention is to reflect the mobility of the terminal (UE), accurate channel estimation based on CSI even in a high-speed moving environment of the terminal (UE) It is to realize a new type of adaptive channel estimation technology that enables

A base station apparatus according to a first aspect of the present invention for achieving the above object includes a reference signal multi-transmission unit for transmitting a specific reference signal (RS) multiple times in successive times; And receiving a plurality of channel state information reported on the basis of each of the specific RSs from a terminal that has received the specific RS transmitted in multiple numbers, and the plurality of channel state information determined at the consecutive time. and a control unit to be used when estimating a channel for a terminal.

Specifically, multiple transmissions of the specific RS and multiple reporting of the channel state information may be activated by a specific identifier transmitted through a predefined field or additionally defined specific field in configuration information related to the specific RS. .

Specifically, the reference signal multi-transmission unit may transmit the specific RS through the same radio resource in multiple slots of the contiguous time, and transmit the specific RS multiple times in the contiguous time.

Specifically, multiple transmissions of the specific RS and multiple reporting of the channel state information are activated according to the moving speed of the terminal or according to a change in transmission performance according to downlink scheduling based on the channel estimation for the terminal. It can be.

Specifically, the number of multiple transmissions of the specific RS and multiple reports of the channel state information is greater when the moving speed of the terminal is higher than when the moving speed is slow, or the channel estimation-based downlink scheduling for the terminal The greater the degradation in transmission performance according to , the greater the decrease in performance compared to the case where the degradation in performance is small.

In order to achieve the above object, a method of operating a base station apparatus according to a second aspect of the present invention includes a reference signal multi-transmission step of transmitting a specific reference signal (RS) multiple times in successive times; And receiving a plurality of channel state information reported on the basis of each of the specific RSs from a terminal that has received the specific RS transmitted in multiple numbers, and the plurality of channel state information determined at the consecutive time. It includes a multi-report reception step to use when estimating a channel for a terminal.

Specifically, multiple transmissions of the specific RS and multiple reporting of the channel state information may be activated by a specific identifier transmitted through a predefined field or additionally defined specific field in configuration information related to the specific RS. .

Specifically, multiple transmissions of the specific RS and multiple reporting of the channel state information are activated according to the moving speed of the terminal or according to a change in transmission performance according to downlink scheduling based on the channel estimation for the terminal. It can be.

A terminal device according to a third aspect of the present invention for achieving the above object includes: a recognition unit for recognizing a data transmission failure situation according to downlink scheduling based on channel estimation; and when the data transmission failure situation is recognized, channel state information on the downlink channel is transmitted to the base station through the fastest uplink channel at the time of the recognition, and the base station performs downlink scheduling based on channel estimation using the channel state information. It includes an information transmission unit to perform.

Specifically, the recognition unit may recognize the data transmission failure situation according to a NACK transmission ratio for data transmitted through a downlink channel within the same frame.

Specifically, the information transmitter may include at least one of a channel state information (CSI) reference signal (RS) and a demodulate reference (DM)-RS received within the same frame in which the data transmission failure situation is recognized. The channel state information can be generated based on one

Specifically, the fastest uplink channel at the time of the recognition may be defined as a reserved channel within a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) within the same frame in which the data transmission failure situation is recognized. can

To achieve the above object, a method of operating a terminal apparatus according to a fourth aspect of the present invention includes a recognition step of recognizing a data transmission failure situation according to downlink scheduling based on channel estimation; and when the data transmission failure situation is recognized, channel state information on the downlink channel is transmitted to the base station through the fastest uplink channel at the time of the recognition, and the base station performs downlink scheduling based on channel estimation using the channel state information. It includes an information transmission step to perform.

Specifically, in the recognizing step, the data transmission failure situation may be recognized according to a NACK transmission ratio for data transmitted through a downlink channel within the same frame.

Specifically, in the information transmission step, in the same frame in which the data transmission failure situation is recognized, among the received Channel State Information (CSI) Reference Signal (RS) and Demodulate Reference (DM)-RS The channel state information may be generated based on at least one.

Specifically, the fastest uplink channel at the time of the recognition may be defined as a reserved channel within a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) within the same frame in which the data transmission failure situation is recognized. can

Therefore, according to the base station apparatus and the operation method of the base station apparatus of the present invention, by reflecting the mobility of the terminal (UE) and enabling accurate channel estimation based on the CSI report even in a high-speed moving environment of the terminal (UE), Downlink transmission performance degradation can be minimized even for a UE that is moving at high speed.

1 is an exemplary view showing a reference signal to which the present invention can be applied.
2 is a diagram showing an example of port support defined for CSI-RS transmission.
3 is an exemplary diagram illustrating a concept of an existing CSI-RS transmission and CSI reporting scheme.
4 is an exemplary view illustrating the concept of multiple CSI-RS transmission and multiple CSI reporting (Bundled CSI-RS transmission & CSI reporting) proposed in the present invention.
5 is a block diagram showing the configuration of a base station device according to an embodiment of the present invention.
6 is a flowchart showing a method of operating a base station apparatus according to an embodiment of the present invention.
7 is an exemplary diagram illustrating a concept of an existing UE non-initiated CSI reporting method.
8 is an exemplary view illustrating a concept of UE-initiated adaptive CSI reporting (UE Initiated CSI feedback) proposed in the present invention.
9 is a block diagram showing the configuration of a terminal device according to an embodiment of the present invention.
10 is a flowchart showing a method of operating a terminal device according to an embodiment of the present invention.

Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention relates to a downlink channel estimation technique using a downlink reference signal (RS).

As shown in FIG. 1, in the LTE system, CRS (Cell-Specific RS) allocated to the entire cell is used as a reference signal (RS) used to know the channel state between the base station and the terminal.

However, the use of such a CRS has limitations limiting the flexibility of network configuration and inefficiency in terms of energy. In addition, the use of CRS is difficult to apply to a high-frequency region of 6 GHz or higher and is not suitable for a multi-input multi-output (MIMO) system using a plurality of antennas.

Accordingly, in NR (5G) using a MIMO system and a high frequency region, instead of using the CRS that has been used in LTE, various types of RSs suitable for various situations of the UE, that is, TRS (Tracking RS), DM-RS (DeModulation RS), CSI-RS (Channel Status Information-RS), PT-RS (Phase Tracking RS), and by giving and receiving RS suitable for each beam of MIMO, It is evolving to respond to various scenarios.

Briefly, TRS is defined for estimation of time/frequency tracking and delay/Doppler spread, and DM-RS is defined for uplink/downlink channel estimation, through which tuning and demodulation are performed. (coherent demodulation) becomes possible. Also, CSI-RS is defined for downlink channel estimation, and PT-RS is defined for phase noise compensation in uplink/downlink channels.

To briefly describe the process of downlink channel estimation using the CSI-RS among the RSs defined in 5G, when the base station (gNB) transmits the CSI-RS, the terminal (UE) performs downlink based on the received CSI-RS. The status (situation) of the link channel is checked/understood and the result (CSI) is reported to the base station (gNB), and the base station (gNB) communicates the downlink channel with the terminal (UE) based on the received CSI Report. It consists of a procedure for estimating the state (situation) of

At this time, the CSI report transmitted by the UE to the base station (gNB) may include a Layer Indicator (LI), a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), a Channel Quality Indicator (CQI), and the like. SS/PBCH Block Resource indicator (SSBRI), L1-RSRP or L1-SINR may be included.

Accordingly, the base station (gNB) may perform channel estimation for the terminal (UE) based on the CSI Report, and based on this channel estimation, downlink scheduling (eg, modulation method, code rate, number of transmission layers, and MIMO) precoding, etc.) can be performed dynamically.

On the other hand, when the terminal (UE) moves at high speed, the downlink channel environment is unstable due to the high-speed movement environment of the terminal (UE), so transmission performance is deteriorated according to downlink scheduling based on channel estimation through the CSI Report. may occur.

However, in the current standard, a method for realizing accurate channel estimation based on a CSI report is not proposed even in a high-speed movement environment of a terminal (UE).

Accordingly, the present invention proposes a new type of adaptive channel estimation technology that enables accurate channel estimation based on a CSI report even when the UE is moving at high speed by reflecting the mobility of the UE. .

In the present invention, in the method of transmitting CSI-RS and reporting CSI, multiple CSI-RS transmission and multiple CSI reporting schemes (hereinafter, Bundled CSI- By newly defining RS transmission & CSI reporting), we intend to realize the proposed adaptive channel estimation technique.

Prior to a detailed description of the present invention, a transmission scheme for CSI-RS will be described first with reference to FIG. 2 .

In existing LTE, CRS was used up to 4 ports and CSI-RS was used after 4 ports, but in 5G (NR), CSI-RS can be used from 1 port to minimize interference and overhead between cells.

2 shows examples of using ports defined for CSI-RS transmission in 5G (NR).

As can be seen in FIG. 2, the CSI-RS transmitted through multi-ports is composed of orthogonal CSI-RSs, and in general, radio resource sharing in the time domain and frequency domain is performed using CDM (Code Division Multiplexing), FDM (Frequency Division Multiplexing) ) and time division multiplexing (TDM).

Hereinafter, adaptive bundled CSI-RS transmission & CSI reporting according to the mobility of a UE to be newly defined/realized in the present invention will be described in detail.

Referring to FIGS. 3 and 4, the concept of Bundled CSI-RS transmission & CSI reporting defined in the present invention can be briefly described.

As can be seen in FIG. 3, conventionally, when a base station (gNB) transmits a CSI-RS in pre-allocated radio resources through a physical downlink shared channel (PDSCH), a terminal (UE) that receives the CSI-RS is mapped to the CSI-RS ( In radio resources of time and frequency to be mapped, CSI is periodically or aperiodically transmitted and reported.

If the UE is moving at high speed, the downlink channel environment is unstable due to the high-speed movement environment, such as the occurrence of Doppler spread according to the high-speed movement of the UE, so according to the conventional method, the Doppler spread Accuracy of channel estimation through the CSI report in an unstable environment such as occurrence is inevitably reduced, and eventually, a problem in that transmission performance according to downlink scheduling based on channel estimation through the CSI report is deteriorated.

Therefore, in the present invention, as shown in FIG. 4, multiple (N) CSI-RSs determined according to the mobility of the UE are transmitted in a bundle form and multiple (M) CSIs are transmitted. Bundled CSI-RS transmission & CSI reporting method, which is reported in the form of a bundle, is proposed.

That is, as can be seen in FIG. 4, in the present invention, the base station (gNB) transmits multiple (N) CSI-RSs in a bundle form at consecutive times through the PDSCH to the terminal (UE) in high-speed movement, The receiving terminal (UE) reports to the base station (gNB) a plurality of (M) CSI as each result of confirming / grasping the state (situation) of the downlink channel based on each CSI-RS in the form of a bundle at consecutive times ( Reporting) can be done.

In this case, in the case of the present invention, since the UE's mobility can be reflected and channel estimation can be performed for the UE in high-speed movement based on the Bundled CSI Report, Even in a high-speed moving environment, accurate channel estimation based on the CSI Report becomes possible.

Hereinafter, with reference to FIG. 5, the configuration of a base station device according to an embodiment of the present invention will be described in detail.

As shown in FIG. 5 , the base station apparatus 100 according to an embodiment of the present invention may include a reference signal multi-transmission unit 110 and a control unit 120.

Furthermore, the base station apparatus 100 according to an embodiment of the present invention, in addition to the above-described configuration, a communication unit (not shown) responsible for communication with nodes in the core network and other base stations and communication functions with the terminal (UE, 10) City) may further include a configuration.

Here, the communication unit (not shown) includes, for example, an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, and a memory, but is not limited thereto, and this function Known circuits that perform may include all.

All or at least part of the configuration of the base station apparatus 100 may be implemented in the form of hardware modules or software modules, or may be implemented in the form of a combination of hardware modules and software modules.

Here, the software module may be understood as, for example, a command executed by a processor that controls operation in the base station device 100, and such a command may have a form loaded in a memory in the base station device 100. .

As a result, the base station device 100 according to an embodiment of the present invention realizes the Bundled CSI-RS transmission & CSI reporting to be defined in the present invention through the above-described configuration, and hereinafter, the base station device 100 for realizing this ) will be described in more detail for each configuration.

The reference signal multi-transmitter 110 is responsible for transmitting multiple (N) specific reference signals (RS) at consecutive times.

Here, the specific RS means an RS that can be used for downlink channel estimation in 5G (NR), and a specific example may be the aforementioned CSI-RS.

That is, the reference signal multi-transmitter 110 may transmit multiple (N) CSI-RSs in a bundle form by transmitting multiple (N) CSI-RSs at consecutive times.

More specifically, the reference signal multi-transmission unit 110 transmits the CSI-RS through the same pre-allocated radio resource in a plurality of (eg, N) slots of consecutive time in the PDSCH, and transmits the CSI-RS. -Bundle transmission that transmits multiple (N) RSs at consecutive times can be implemented.

The control unit 120 reports, based on each CSI-RS, from the terminal 10 that has received specific RSs, for example, CSI-RSs transmitted by the reference signal multi-transmission unit 110 in multiples (N). By receiving multiple (M) pieces of channel status information (CSI, Channel Status Information), multiple (M) pieces of channel status information, that is, multiple (M pieces) of CSI reports determined at the consecutive time, are provided to the terminal 10 It is responsible for the function to be used when estimating the channel for .

That is, the control unit 120 determines each of the multiple (M) CSIs that the terminal 10, which receives multiple (N) CSI-RSs transmitted in a bundle form, confirms/recognizes based on each CSI-RS. If it is reported in the form of a bundle, it is possible to receive the Bundled CSI Report for the Bundled CSI-RS transmitted at the previous consecutive time by receiving it.

Accordingly, the control unit 120 transmits the Bundled CSI Report to a separate functional unit (not shown) that performs CSI report-based channel estimation, and multiple (M) CSI reports in the separate functional unit (not shown). Can be used when estimating a channel for the terminal 10.

Of course, if the control unit 120 is in charge of a function of performing CSI report-based channel estimation, it may directly perform channel estimation for the terminal 10 using a bundled CSI report, that is, multiple (M) CSI reports. there is.

In this case, in the present invention, even if the downlink channel environment such as Doppler spread is unstable due to the high-speed movement environment of the terminal (UE), in continuous time in the overall process of CSI report-based channel estimation such as Doppler estimation Doppler (Doppler estimation) Since the Bundled CSI report for the Bundled CSI-RS can be used, accurate channel estimation based on the CSI Report is possible.

On the other hand, according to an embodiment of the present invention, multiple transmissions of the aforementioned specific RS (CSI-RS) and multiple reports of channel state information (CSI), that is, bundled CSI-RS transmission & CSI reporting, the movement of the terminal 10 It can be activated according to speed.

For example, the base station apparatus 100 of the present invention can predict the movement speed of a terminal for each terminal.

In the present invention, the method of predicting the movement speed of the terminal is not limited, but an example is described based on TA (Timing Advance), which varies according to the distance between the base station apparatus 100 and the terminal 10, the base station The movement speed of the terminal 10 can be predicted from the device 100 side.

Therefore, the base station apparatus 100 of the present invention predicts the movement speed for each terminal through various methods such as a TA-based prediction method, and determines that it is moving at a high speed (eg, a threshold speed or higher, or a preset high speed movement speed range) For the UE 10, Bundled CSI-RS transmission & CSI reporting defined by the present invention may be activated.

On the other hand, when the terminal 10 moves at high speed, most of the degradation in transmission performance due to downlink scheduling performed based on channel estimation through the CSI Report of the terminal 10 occurs, so that the downlink based on channel estimation When transmission performance degradation due to link scheduling is confirmed, it may be indirectly predicted that the terminal 10 is moving at high speed.

Therefore, according to an embodiment of the present invention, bundled CSI-RS transmission & CSI reporting may be activated, or may be activated according to a change in transmission performance according to downlink scheduling based on channel estimation for the terminal 10.

For example, the base station apparatus 100 of the present invention can check the transmission performance of each terminal transmitting downlink data according to downlink scheduling based on channel estimation through a CSI Report.

Accordingly, the base station apparatus 100 of the present invention, for the terminal 10 for which transmission performance degradation due to data transmission failure (eg, transmission of NACK L times due to transmission failure) is confirmed, Bundled CSI defined by the present invention -RS transmission & CSI reporting can be activated.

Furthermore, according to an embodiment of the present invention, the number of multiple transmissions of the aforementioned specific RS (CSI-RS) and multiple reports of channel state information (CSI), that is, the number of Bundled CSI-RS transmissions & CSI reports, is the terminal ( 10) can be determined according to the moving speed.

For example, the base station apparatus 100 of the present invention, for the terminal 10 activating the bundled CSI-RS transmission & CSI reporting of the present invention, when the moving speed of the terminal 10 is faster, the moving speed is slower By determining the number of transmissions (N) of multiple CSI-RSs and the number of reports (M) of CSIs to a large number, the faster the mobile station, the more bundled CSI-RSs it transmits and receives a large number of bundled CSI reports. can do.

Meanwhile, according to an embodiment of the present invention, the number of multiple transmissions of the aforementioned specific RS (CSI-RS) and multiple reports of channel state information (CSI), that is, the number of bundled CSI-RS transmissions & CSI reports, is ) may be determined according to a change in transmission performance according to downlink scheduling based on channel estimation for .

As described above, the deterioration in transmission performance due to downlink scheduling performed based on the channel estimation through the CSI Report of the terminal 10 becomes larger as the terminal 10 moves at a higher speed, so the channel estimation based It can be indirectly predicted that the higher the transmission performance degradation due to the downlink scheduling of , the higher the mobile terminal 10 is.

Accordingly, for example, the base station apparatus 100 of the present invention, for the terminal 10 activating the bundled CSI-RS transmission & CSI reporting of the present invention, the greater the transmission performance degradation due to data transmission failure, the greater the transmission performance degradation. By determining the number of multiple transmissions (N) of CSI-RS and the number of multiple reports (M) of CSI-RS compared to the case where is small, the UE indirectly predicted to move at high speed transmits a large number of bundled CSI-RSs, Bundled CSI Report can be received by number.

In this case, in the present invention, according to the mobility of the UE (UE) in high-speed movement, multiple (N) CSI-RS are transmitted in a bundle form and multiple (M) CSI are reported in a bundle form By newly defining the Bundled CSI-RS transmission & CSI reporting method, accurate channel estimation based on the CSI Report will be possible even in a high-speed mobile environment where channel estimation is difficult due to Doppler spread.

On the other hand, multiple transmissions of specific RSs (CSI-RSs) and multiple reports of channel state information (CSI), that is, Bundled CSI-RS transmission & CSI reporting, are previously defined in configuration information related to specific RSs (CSI-RSs). It can be activated by a specific identifier transmitted through a specified field or a specific field that is additionally defined.

Specifically, the base station (gNB) is based on transmitting configuration information (e.g., CSI configuration) for this to the terminal prior to the downlink channel estimation process using CSI-RS, and such configuration information (e.g., CSI configuration ) may include a CSI-RS transmission method, a location of a radio resource transmitting the CSI-RS, CSI report-related information (eg, CSI report config.), and the like.

Accordingly, according to one embodiment, in the present invention, configuration information related to CSI-RS transmitted to the terminal, in particular, "Bundled CSI" that can be used in the CSI report field predefined in CSI report-related information (eg, CSI report config.) - A specific identifier for “activating RS transmission & CSI reporting” may be additionally defined.

In this case, the base station apparatus 100 of the present invention relates to CSI reporting for the terminal 10 determined to be moving at high speed or the terminal 10 whose transmission performance is degraded according to downlink scheduling based on channel estimation. Bundled CSI-RS transmission & CSI reporting can be activated by transmitting a specific identifier through a predefined CSI report field in information (eg, CSI report config.).

According to another embodiment, in the present invention, a specific field for bundled CSI-RS transmission & CSI reporting (eg, CSI report config.) in configuration information related to CSI-RS transmitted to a terminal, particularly CSI report-related information (eg, CSI report config.) : B-CSI-report-Config.) can be additionally defined.

In this case, the base station apparatus 100 of the present invention relates to CSI reporting for the terminal 10 determined to be moving at high speed or the terminal 10 whose transmission performance is degraded according to downlink scheduling based on channel estimation. Bundled CSI-RS transmission & CSI reporting may be activated by transmitting a specific identifier through a specific field (eg, B-CSI-report-Config.) additionally defined in information (eg, CSI report config.).

As described above, in the base station apparatus according to the embodiment of the present invention, in the method of transmitting CSI-RS and reporting CSI, Bundled CSI- By newly defining RS transmission & CSI reporting, an adaptive channel estimation technology that reflects the mobility of the UE and enables accurate channel estimation based on the CSI Report is realized.

For this reason, in the present invention, the effect of minimizing downlink transmission performance degradation for a UE that is moving at high speed by enabling accurate channel estimation based on the CSI Report by reflecting the mobility of the UE is achieved. derive

Hereinafter, a method of operating a base station apparatus according to an embodiment of the present invention will be described with reference to FIG. 6 .

In the operating method of the base station apparatus according to an embodiment of the present invention, the base station apparatus 100, for each terminal transmitting downlink data according to downlink scheduling based on channel estimation through a CSI Report, is newly introduced in the present invention. It is determined whether the defined Bundled CSI-RS transmission & CSI reporting are necessary (S110).

According to an embodiment, in the present invention, a terminal that is determined to be moving at a high speed (eg, a threshold speed or higher, or a preset high speed moving speed range) by predicting a moving speed for each terminal through various methods such as a TA-based prediction method ( For 10), it may be determined that Bundled CSI-RS transmission & CSI reporting are required.

According to another embodiment, in the present invention, for the terminal 10 in which transmission performance degradation (eg, L NACK transmission due to transmission failure) is confirmed according to downlink scheduling based on channel estimation, the Bundled CSI-RS It may be determined that transmission & CSI reporting is necessary.

In the operating method of the base station apparatus according to an embodiment of the present invention, the base station apparatus 100, for the terminal 10 determined to require Bundled CSI-RS transmission & CSI reporting, configuration information related to CSI-RS, particularly CSI Bundled CSI-RS transmission & CSI reporting of the present invention are activated for the terminal 10 by transmitting a specific identifier through a pre-defined field or a specific field additionally defined in report-related information (eg, CSI report config.) It can be done (S120).

According to an embodiment, in the present invention, a specific identifier is transmitted to the terminal 10 through a CSI report field predefined in CSI report-related information (eg, CSI report config.), and Bundled CSI- RS transmission & CSI reporting can be activated.

According to another embodiment, in the present invention, for the terminal 10, a specific field for bundled CSI-RS transmission & CSI reporting (eg, B-CSI-report) in CSI report-related information (eg, CSI report config.) -Config.) is additionally defined and a specific identifier is transmitted through an additionally defined specific field (eg, B-CSI-report-Config.), and Bundled CSI-RS transmission & CSI reporting can be activated.

Then, in the operating method of the base station apparatus according to the embodiment of the present invention, the base station apparatus 100 transmits multiple CSI-RSs at consecutive times to the terminal 10 that has activated Bundled CSI-RS transmission & CSI reporting. By transmitting (N), multiple (N) CSI-RSs can be transmitted in a bundle form (S130).

Specifically, the base station apparatus 100 transmits the CSI-RS through the same radio resource pre-allocated within a plurality of (eg, N) slots of consecutive times in the PDSCH, and transmits the CSI-RS at consecutive times. Bundle transmission that is transmitted in multiple (N) can be implemented in (S130).

In the present invention, the terminal 10 receiving multiple (N) CSI-RSs transmitted in a bundle form from the base station device 100 checks/determines the channel state based on each CSI-RS (S140 ), the terminal 10 reports a plurality (M) of each CSI generated by identifying the channel state based on each CSI-RS in the form of a bundle (S150).

To explain an example, the terminal 10 identifies a channel state based on each CSI-RS and transmits multiple (M) of each CSI report generated by multiple (eg, M) slots of consecutive time in the PUSCH. It is possible to implement a bundle type report that transmits multiple (M) CSI reports at consecutive times by transmitting through the same radio resource pre-allocated within (slot).

Therefore, in the operating method of the base station apparatus according to an embodiment of the present invention, the base station apparatus 100, from the terminal 10 to receive a number (N) of CSI-RS transmitted in a bundle form, The Bundled CSI Report for the Bundled CSI-RS transmitted on time can be received.

Therefore, in the operating method of the base station apparatus according to the embodiment of the present invention, the base station apparatus 100 estimates the channel based on the CSI report for the terminal 10 using a Bundled CSI Report, that is, multiple (M) CSI reports. can also be performed directly.

Then, in the operating method of the base station device according to the embodiment of the present invention, the base station device 100, for the terminal 10 in high-speed movement, in the overall process of CSI report-based channel estimation such as Doppler estimation (Doppler estimation) Since the Bundled CSI report for the Bundled CSI-RS in continuous time can be used, accurate channel estimation based on the CSI Report is possible, and downlink scheduling (e.g., modulation method, code rate, transmission) based on accurate channel estimation is possible. number of layers, MIMO precoding, etc.) can be performed (S160).

In the operating method of the base station device according to the embodiment of the present invention, the base station device 100, unless the Bundled CSI-RS transmission & CSI reporting operation of the present invention is turned off (S170 No), the above-described step S110 and thereafter You can do it step by step.

As described above, in the operating method of the base station apparatus according to the embodiment of the present invention, in the method of transmitting the CSI-RS and reporting the CSI, for adaptively performing according to the mobility of the terminal (UE) By newly defining bundled CSI-RS transmission & CSI reporting, an adaptive channel estimation technology is realized that enables accurate channel estimation based on the CSI Report by reflecting the mobility of the UE.

For this reason, in the present invention, the effect of minimizing downlink transmission performance degradation for a UE that is moving at high speed by enabling accurate channel estimation based on the CSI Report by reflecting the mobility of the UE is achieved. derive

On the other hand, in the present invention, in the CSI reporting method, by reflecting the mobility of the UE (UE), the UE-led adaptive CSI reporting (hereinafter referred to as UE Initiated CSI feedback) is newly defined, The proposed adaptive channel estimation technique may be realized.

Hereinafter, UE Initiated CSI feedback reflecting mobility of a UE to be newly defined/realized in the present invention will be described in detail.

First, with reference to FIGS. 7 and 8, the concept of UE Initiated CSI feedback defined in the present invention can be briefly described.

Conventionally, when a base station (gNB) transmits a CSI-RS, a terminal (UE) that receives it transmits a CSI Report in radio resources of time and frequency mapped to the CSI-RS, and the base station (gNB) Downlink scheduling based on channel estimation can be performed by performing channel estimation for the UE based on the CSI Report.

However, except for the case where the CSI Report is defined for every frame (Fame), as can be seen in FIG. 7, even if the transmission performance is deteriorated during downlink data transmission, the Up to this point, there may be a problem in that downlink transmission performance is continuously deteriorated/maintained.

For example, FIG. 7 shows a case where multiple (eg, L) transmission failures (NACKs) occur in the same Frame (n-1) due to rate adaptation mismatch in downlink scheduling based on channel estimation.

In this case, conventionally, when the terminal (UE) reports a downlink transmission failure (NACK) to the base station (gNB), the base station (gNB) transmits a CSI Report trigger based on this, and causes the terminal (UE) to send the CSI Report. By transmitting, channel estimation based on the CSI Report and downlink scheduling based on channel estimation can be re-performed.

That is, in the past, even if a downlink transmission failure (NACK) occurs in the same Frame (n-1), the CSI Report is not transmitted in the same Frame (n-1) and is transmitted in the UL channel of the next Frame (n), Since the downlink transmission of the next Frame (n) before the CSI Report transmission follows the downlink scheduling based on the previous channel estimation, there is a high possibility that transmission failure will continue due to the rate adaptation mismatch.

Accordingly, as shown in FIG. 8, when a downlink transmission failure (NACK) occurs in Frame (n-1), the UE that recognizes this proactively transmits the latest CSI in the same Frame (n-1). To propose a UE Initiated CSI feedback scheme.

That is, in the present invention, when a downlink transmission performance degradation (eg, downlink transmission failure) is recognized, a UE that recognizes this can proactively generate and transmit CSI in the same frame in which the performance degradation is recognized. .

On the other hand, if the terminal (UE) is moving at high speed, the downlink channel environment is unstable due to the high-speed movement environment such as Doppler spread caused by the high-speed movement of the terminal (UE), so according to the conventional method, the Doppler spread Since the accuracy of channel estimation through the CSI report in an unstable environment such as occurrence is inevitably lowered, it is highly likely to lead to rate adaptation mismatch in downlink scheduling based on channel estimation.

As a result, in the present invention, a terminal that recognizes a decrease in downlink transmission performance (eg, downlink transmission failure) due to the fact that a decrease in downlink transmission performance based on channel estimation occurs during high-speed movement of the terminal (UE). (UE, which is highly likely to be moving at high speed) proactively transmits CSI in the same frame in which it recognizes it, so that the correct channel is available at the right/early time based on the CSI feedback transmitted from the fast-moving UE (UE). estimation can be made possible.

Hereinafter, with reference to FIG. 9, the configuration of a terminal device according to an embodiment of the present invention will be described in detail.

As shown in FIG. 9 , a terminal device 10 according to an embodiment of the present invention may include a recognition unit 12 and an information transmission unit 14 .

Furthermore, the terminal apparatus 10 according to an embodiment of the present invention may further include a configuration of a communication unit (not shown) in charge of a communication function with the base station (gNB, 100) in addition to the above configuration.

Here, the communication unit (not shown) includes, for example, an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, and a memory, but is not limited thereto, and this function Known circuits that perform may include all.

All or at least part of the configuration of the terminal device 10 may be implemented in the form of a hardware module or a software module, or may be implemented in a combination of a hardware module and a software module.

Here, a software module may be understood as, for example, a command executed by a processor that controls operation within the terminal device 10, and such a command may have a form loaded in a memory within the terminal device 10. .

Eventually, the terminal device 10 according to an embodiment of the present invention realizes the UE Initiated CSI feedback to be defined in the present invention through the above-described configuration, and hereinafter, each component in the terminal device 10 to realize this will be described in more detail.

The recognition unit 12 is responsible for recognizing a data transmission failure situation according to downlink scheduling based on channel estimation.

More specifically, the recognition unit 12 may recognize the data transmission failure situation according to a NACK transmission ratio for data transmitted through a downlink channel within the same frame.

For example, referring to FIG. 8, the recognition unit 12 performs an error check (e.g., CRC, Cyclic Redundancy) on data transmitted through a downlink channel, that is, a PDSCH, in a frame unit. Based on the transmission failure (NACK) that is transmitted after checking, it is possible to recognize the data transmission failure situation.

As an example, if the transmission rate of transmission failure (NACK) within the same frame is greater than or equal to a predetermined set value (eg, L times), the recognition unit 12 sets the data transmission failure situation according to downlink scheduling based on channel estimation. can perceive

When the recognition unit 12 recognizes a data transmission failure situation, the information transmission unit 140 transmits channel state information (CSI) for the downlink channel to the base station 100 through the fastest uplink channel at this time of recognition. Thus, the base station 100 is responsible for performing downlink scheduling based on channel estimation using the CSI.

Here, the fastest uplink channel at this time of recognition may be defined as a reserved channel within a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) within the same frame in which the data transmission failure situation is recognized. .

That is, referring to FIG. 8, in the present invention, CSI transmission according to the UE Initiated CSI feedback of the present invention can be additionally defined in a reserved channel available in PUCCH or PUSCH in units of frames.

Accordingly, the information transmission unit 140, when the recognition unit 12 recognizes a downlink transmission failure situation (eg, NACK L times, L = 3) in Frame (n-1), for the downlink channel After generating the latest CSI, the CSI can be transmitted to the base station 100 through a reserved channel within the PUCCH or PUSCH defined for CSI transmission in the same frame (n-1) in which the data transmission failure situation is recognized.

At this time, the information transmitter 140 updates the latest CSI for the downlink channel based on at least one of the received CSI-RS and DM-RS within the same Frame (n-1) in which the data transmission failure situation is recognized. can create

To explain an example, the information transmission unit 140 may generate CSI for a downlink channel based on the most recent CSI-RS that was not used as a basis when generating a previous CSI report, and this may be used in a data transmission failure situation. It can be transmitted to the base station 100 through a reserved channel of PUCCH or PUSCH within the same recognized frame (n-1).

Describing a more specific embodiment, the information transmission unit 140 transmits information to a downlink channel based on the most recent CSI-RS not used as a basis for generating a previous CSI report as well as consecutive DM-RSs included in the PDSCH. CSI for the CSI can be generated and transmitted to the base station 100 through a reserved channel of PUCCH or PUSCH within the same Frame (n-1) in which the data transmission failure situation is recognized.

Of course, the information transmission unit 140 may generate CSI for the downlink channel based only on the continuous DM-RS included in the PDSCH, and generate CSI for the downlink channel within the same Frame (n-1) in which the data transmission failure situation is recognized. It can be transmitted to the base station 100 through a reserved channel of PUCCH or PUSCH.

In this case, in the present invention, a UE (UE, highly likely to be in high-speed movement) recognizing a decrease in downlink transmission performance (eg, downlink transmission failure) proactively transmits CSI in the same frame in which it recognizes it. Since the base station 100 can transmit, the base station 100 can accurately estimate the channel at the right/early time based on the CSI feedback transmitted from the fast-moving terminal (UE).

As described above, in the terminal device according to the embodiment of the present invention, due to the fact that the downlink transmission performance based on channel estimation is degraded when the terminal (UE) moves at high speed, the mobility of the terminal (UE) Mobility) by newly defining UE Initiated CSI feedback in which the UE proactively generates and transmits CSI at the right time/early time, reflecting the mobility of the UE (UE), an accurate channel based on CSI feedback It realizes an adaptive channel estimation technique that enables estimation. .

For this reason, in the present invention, by reflecting the mobility of the terminal (UE), and enabling accurate channel estimation based on CSI feedback transmitted from the terminal (UE) moving at the right time/early time, An effect of minimizing downlink transmission performance degradation is derived for the terminal (UE) as well.

On the other hand, the "CSI Report" and "CSI feedback" described above have the same role used in channel estimation for the downlink channel of the terminal (UE) in the base station (gNB) receiving them, except that "UE Initiated It is referred to as "CSI Report" and "CSI feedback" depending on whether it is " or "UE Initiated".

Furthermore, the two technologies proposed by the present invention, that is, Bundled CSI-RS transmission & CSI reporting and UE Initiated CSI feedback, may be separately implemented, and both technologies proposed by the present invention may be used in the same system. might be implemented.

Hereinafter, a method of operating a terminal device according to an embodiment of the present invention will be described with reference to FIG. 10 .

In the operating method of the terminal device according to the embodiment of the present invention, the terminal device 10 determines whether UE Initiated CSI feedback newly defined in the present invention is necessary (S10).

According to an embodiment, the terminal device 10 may determine that UE Initiated CSI feedback is required when a data transmission failure situation according to downlink scheduling based on channel estimation is recognized.

Specifically, for example, in the present invention, transmission failure (for example, CRC, Cyclic Redundancy Check) transmitted after error checking (e.g., CRC, Cyclic Redundancy Check) on data transmitted through a downlink channel in the same frame, that is, PDSCH, in units of frames NACK), if the transmission rate of transmission failure (NACK) within the same frame is more than a preset setting value (eg, L times), it can be recognized as a data transmission failure situation according to downlink scheduling based on channel estimation.

Therefore, in the operating method of the terminal device according to the embodiment of the present invention, the terminal device 10 generates the latest CSI for the downlink channel when it recognizes a data transmission failure situation and determines that UE Initiated CSI feedback is necessary. Do (S20).

In detail with reference to FIG. 8, when the terminal device 10 recognizes a downlink transmission failure situation (eg, L NACK occurrence, L = 3) in Frame (n-1), a data transmission failure situation Within this recognized same frame (n-1), the latest CSI for the downlink channel can be generated based on at least one of the received CSI-RS and DM-RS.

Describing a more specific embodiment, the terminal device 10, within the same Frame (n-1) in which the data transmission failure situation is recognized, the most recent CSI-RS and PDSCH not used as a basis for generating the previous CSI report The CSI for the downlink channel can be generated based on the continuous DM-RS included in the CSI.

And, in the operating method of the terminal device according to the embodiment of the present invention, the terminal device 10 transmits the CSI for the downlink channel generated in step S20 to the same frame in which the data transmission failure situation was recognized this time (n-1 ) can be transmitted to the base station 100 through a pre-defined reserved channel of PUCCH or PUSCH (S30).

That is, in the present invention, a UE (UE, highly likely to be in high-speed movement) recognizing a decrease in downlink transmission performance (eg, downlink transmission failure) proactively generates CSI in the same frame in which it recognizes it. and to transmit.

In this case, in the present invention, the base station 100 can accurately estimate the channel at the right time/early time based on the CSI feedback transmitted from the fast-moving terminal (UE), and thus, the downlink scheduling based on the channel estimation is timely. / It can be performed again at an early point (S40).

In the operating method of the terminal device according to the embodiment of the present invention, the terminal device 10 continues the above-mentioned steps S10 and thereafter unless the UE Initiated CSI feedback operation of the present invention is turned off (S50 No) can be done

As described above, in the operating method of the terminal device according to the present invention, the mobility of the terminal (UE) is due to the fact that the downlink transmission performance based on channel estimation is degraded when the terminal (UE) moves at high speed. Mobility) by newly defining UE Initiated CSI feedback in which the UE proactively generates and transmits CSI at the right time/early time, reflecting the mobility of the UE (UE), an accurate channel based on CSI feedback It realizes an adaptive channel estimation technique that enables estimation. .

For this reason, in the present invention, by reflecting the mobility of the terminal (UE), and enabling accurate channel estimation based on CSI feedback transmitted from the terminal (UE) moving at the right time/early time, An effect of minimizing downlink transmission performance degradation is derived for the terminal (UE) as well.

The method of operating a base station apparatus and a terminal apparatus according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the medium may be those specially designed and configured for the present invention or those known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to act as one or more software modules to perform the operations of the present invention, and vice versa.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the following claims. Anyone skilled in the art will extend the technical spirit of the present invention to the extent that various variations or modifications are possible.

According to the base station apparatus and operating method of the base station apparatus of the present invention, the existing technology is realized in terms of realizing a new adaptive channel estimation technology that enables accurate channel estimation based on CSI by reflecting the mobility of a terminal (UE). As it goes beyond the limits of related technology, it is an invention with industrial applicability because it is not only available for use in related technology, but also has a sufficient possibility of marketing or business of the applied device, as well as a level that can be clearly implemented in reality.

10: Terminal
100: base station device
110: reference signal multi-transmission unit 120: control unit

Claims (8)

A reference signal multi-transmission unit for transmitting a specific reference signal (RS) multiple times in successive times; and
Receives a plurality of channel state information reported on the basis of each of the specific RSs from the terminal that has received the specific RS transmitted in multiple numbers, and transmits the plurality of channel state information determined at the consecutive time to the terminal A base station apparatus comprising a control unit to be used when estimating a channel for. According to claim 1,
Multiple transmissions of the specific RS and multiple reporting of the channel state information,
The base station apparatus, characterized in that activated by a specific identifier transmitted through a predefined field or additionally defined specific field in configuration information related to the specific RS. According to claim 1,
The reference signal multi-transmission unit,
The base station apparatus characterized in that the specific RS is transmitted through the same radio resource in multiple slots of the contiguous time, and the specific RS is transmitted multiple times in the contiguous time. According to claim 1,
Multiple transmissions of the specific RS and multiple reporting of the channel state information,
Activated according to the movement speed of the terminal, or
The base station apparatus, characterized in that activated according to a change in transmission performance according to downlink scheduling based on the channel estimation for the terminal. According to claim 1,
The number of multiple transmissions of the specific RS and multiple reports of the channel state information,
The faster the moving speed of the terminal is, the higher the moving speed is compared to the lower moving speed; or
The base station apparatus, characterized in that the greater the transmission performance degradation according to the downlink scheduling based on the channel estimation for the terminal, the greater the performance degradation compared to the case where the performance degradation is small. A reference signal multi-transmission step of transmitting a specific reference signal (RS) multiple times in successive times; and
Receives a plurality of channel state information reported on the basis of each of the specific RSs from the terminal that has received the specific RS transmitted in multiple numbers, and transmits the plurality of channel state information determined at the consecutive time to the terminal A method of operating a base station apparatus comprising a multi-report reception step for use in channel estimation for . According to claim 6,
Multiple transmissions of the specific RS and multiple reporting of the channel state information,
A method of operating a base station apparatus, characterized in that activated by a specific identifier transmitted through a predefined field or additionally defined specific field in configuration information related to the specific RS. According to claim 6,
Multiple transmissions of the specific RS and multiple reporting of the channel state information,
Activated according to the movement speed of the terminal, or
A method of operating a base station apparatus, characterized in that activated according to a change in transmission performance according to downlink scheduling based on the channel estimation for the terminal.

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